Endless Extension Of Life Cycle Of Construction And Demolition Wastes As The Most Efficient Environmental Technology

The main purposes of this study were to confirm the life cycle assessment of traditional construction materials (construction and demolition debris, plaster waste lime production waste) as endless due to the possibility of reusing them multiple times without reducing their mechanical properties and sustainability; to determine the physical-chemical processes of recycled composites structure formation. The research was performed by the methods of X-ray powder diffraction, scanning electron microscopy, energy dispersive spectroscopy, and laser micro mass analyses. The sample's axial resistance reached 3.2 MPa on the 3rd day, 8.8 MPa on the 14th day, and up to 16.7 MPa on the 180th day with expansion coefficient values up to 1.81%, water absorption - 14.9%, and apparent density up to 1.95 g/cm(3). The processes of structure formation showed the hardening of the material due to alkaline corrosion of the solid particles' surfaces with chemical interaction of these alkaline solutions and synthesis of new predominantly amorphous formations of sol-gel CSH-group and carbonates; over time, these new gel formations were converted into a stony state. The obtained results show that developed composites can be returned unlimited times to construction life cycle as valuable components to produce building materials without the use of traditional natural raw materials like sand, rock, stones, clay, and to avoid irreparable destruction of landscapes by quarries for their extraction. (C) 2021 Elsevier B.V. All rights reserved.